Feed control mechanism for lathes



Sept. 16, 1952 K. c. JOHNSON 2,610,535

FEED CONTROL MECHANISM FOR LATHES Filed D60. 29, 1949 2 SHEETS-SHEET 1 F i g. 2 V ZYVNOR.

ATTORNEY p 1952 K. c. JOHNSON 2,610,535

FEED CONTROL MECHANISM FOR LATHES.

Filed Dec. 29, 1949 2 SHEETS-SHEET 2 IN VENT OR.

ATTORNEY Patented Sept. 16, 1952 Application December 29, 1949', seri ivnissmr, 4c1ai s; (Cl. ,82-,-23)' V The present invention relates to lathe control mechanism, and has particular reference to a novel arrangement for thread cutting;-

The principal object of the invention is to provide a control which starts and'stop's longitudinalfeed of the cutting tool and simultaneously cross feeds the tool inwardly and outwardly of the cut. a 3 I Another object of this invention is to facilitate the cutting screw threads on a screw cutting lathe by connecting the cross feed and the longitudinal feed to operate simultaneously. Another object is to provide a release mechan'i'sm which disengages the half nut from the lead screw to stop inward motion of the crosssli'de and simultaneously rotates the cross feed handle to back the cutting tool out of the out. Another object of the invention is to eliminate setting'stops forthe cross slide 'for proper inward or outward setting Qfthe'cutting tool at the beginning or end of each successive cut.

- :An additional object of the invention is to iacilitatecutting a screw thread to the desired length.

..--'.An additional object of the invention is to -prov ide means whereby-the cross fee'dmechanism. can be reversedso that either internalnor externalthreads can .be cut.

. A iurther object Ofll'lhe invention is new ,vide a controllwhich prevents damage to. the tool and the chuckor other work holdingrmechanism by eliminating over-recessing.

7 Another object is to regulate the travel.

.the cross slide when cutting internal threads the device by sliding one control knob-into pofio rr V With the above and other objects and ad Ivantajgeous features in 'view, the invention consists of a novel arrangement of parts more fully disclosed in the detailed description following, in' conjunction with the accompanying drawings, and more specifically defined in the claims app'ended'thereto. Y

In the drawings,

Fig. 1 is a top plan view of a lathe carriage :and its associated parts;

7 Fig. 2 is a front elevation of Fig. 1; v r

Fig. 3 is an enlarged sectional detail of the novel control on the line 3-3-of-'Fig. 2 partly broken away; and

, .7 Fig. 4 isan exploded view oi -the parts of It has been-found desirable to provide a simple. and effective control for a lathe whereby screw thread cutting is facilitated. ToJthis' end,-. I

have devised a mechanism which links the longitudinal screwfeed and the cross slideffeed parts together so that thelshifting of one lever will di'sengagetheihalf nut parts from the lead o screw and rotate the cross slide screwshaft to thestandard handle [2. This assembly in turn is mounted upon the crossslide l3, which slides upon thedovetail M at right angles to the axis of the work being turned, and is, manually shiftable by. a standardhandle lfi'through the cross slide .screw l6 and the cross slide screw nut, indicated in dotted lines, fastened in the cross'slide I3.' g

. Longitudinalfeed of the cutting tool I0 is obtained by turning a half nut lever 11 to rotate a half nut cam l8, to thereupon move the upper and lower half nuts (not shown) into engagement' with the longitudinal feed screw I9 in the usual manner. I interlock the cross feed mechanism with the longitudinal; feed mechanism so that movement of the half nut lever I! for engaging or disengaging the longitudinal screw feed also shifts the cross slide l3 inwardly into tool cutting position. 7

I preferably accomplish this interlocking by putting a diametrical slot 20 in the half nut cam I8 in which an adjustable slide lever 2| is mounted, the slide lever 2| having a longitudinal elongated hole 22 cooperating with a reduced bearing section 23 of a mounting screw 24 which is threadedlysecured into the lathe apron. The slide levermay be adjusted in the slot 20 for a purpose hereinafter explained.

The upper end 25 of the slide lever 2| is extended to be received between two'spaced cars 26, 21 at one end of a link 28, the ears openings and being pivotally secured together by a pivot pin 29. The other end 3!] of the link 28 has spaced ears 3|, 32 for pivotal securing to a lateral extension 33 of the inner portion 34 of a dog clutch 35, by means of a pivot pin 36 which extends through aligned openings in the ears 3!, 32 and the extension 33.

The clutch is rotatably mounted on an intermediate section 31 and an outer section 38 of a stepped shaft 39 which is rotatably mounted in the lathe apron and which has an inner section 40 of smaller diameter. The inner shaft section 40 carries a standard cross feed gear pinion 4i and a cross feed gear 42, see Fig. 3, which are keyed thereto. The cross feed gear pinion 4i and the cross feed gear 42 are in mesh with the cross slide screw pinion 43 and are free to rotate when the lathe is set up for threading. its purpose being to form a gear train for the power cross feed.

The outer portion 44 of the clutch-35 is castellated to provide teeth 45 for meshing with cooperating teeth 43 of the inner portion 34., and

.is slidably keyed to theouter section 38 of the stepped shaft 39, the outer portion 44 being provided with :an enlarged knurled section 4'1. The outer shaft section 38 has a transverse recess 48 in. which a spring pressed friction ball 49 is positioned, and the outer clutch portion 44 has two longitudinally spaced openings 50, 5| for selectively receiving the ball d9 to releasably retain the outer portion 44 with its teeth 45 disengaged or engaged with the teeth 46.

A large headed screw 52 and a washer 53,

see Fig. 3, are mounted on the outer end 38 of the stepped shaft 39 'to engage an innershoulder 5'4 of the outer portion 44 to lock it against removal, and a nut 55 is secured to the inner reduced threaded end 56 of the stepped shaft '39 to lock the cross feed gear 42 and the cross feed gear pinion 4| in place.

The operation of the novel control may now be explained. When the tool has been set, and the cross slide 13 brought to an approximate cutting position manually, the outer clutch portion 44 is shifted to engaged position, thus connecting the cross feed gearing to the half nut cam'lB through the stepped shaft 39., outer ,por tion 44, inner portion '34, line .28 and adjustable slide lever 2i. cam' l8 by means of the half nut lever '11 to disengage the half nut from the lead screw IQ simultaneously rotates the cross feedsgearing and moves the cross slide 13 to back the tool out of the out; when the half nut lever I1 is moved to engage the lead screw, the crossfeed'gearing'is also moved inwardly to move the cross slide to the previously set position. Further adjustment of the cutting tool is effected by advancing the compound rest ll through the standard handle The extent of automatic movement of the cross slide !3 can be readily regulatedby shifting the adjustable slide lever 2| in the slot?!) and looking it in'the desired position by the screw '24. This eliminates the need for cross slide stops as the cross slide l3 stops at the same'position each time the mechanism is actuated. The adjustable feature of the'cross slide 13 isparticula'r- 1y advantageous in cutting internal threads as the travel of the cross slide l3 can be regulated so that the cutting tool holder will not strike the opposite sideof the hole when backing out of the out.

A rotation of the half nut Further, the control mechanism can be readily disengaged by means of the outer clutch portion 44 for facing work or for normal turning, and can be easily reversed by setting the inner clutch portion 34 in a downward position to rotate the cross feed gearing in the opposite direction for the same previous motion of the half nut cam i8, thus bringing the cross slide [3' outwardly as thehalf nuts are engaged. The cooperating screw feed and cross feed movements are particularly suitable for starting'a thread next to a shoulder, by reversing the lathe and cutting from the rear or inverting the tool, as the cross feed begins as the half nuts are engaged.

Although I have disclosed a specific embodiment of the invention, it is obvious that changes in the arrangement, number and operation of the parts may be made to adapt the control mechanism for different sizes and types of screw cutting lathes, without departing from the spirit or the scope of the invention as defined in the claims appendedhereto.

I claim: V

l. A control mechanism for a lathe having a tool carrier, a longitudinal feed screw, releasable lock means operatively connecting the tool carrier and the longitudinal feed screw, and a manually settable cross slide on said tool carrier,

comprising a cam movabl'e to lock and unlock the releasable lock mechanism, and mechanism connecting the cam tothe cross slide for simultaneously moving. the cross slide inwardly on looking movement and outwardly on unlocking comprising a cam movable to lock'and unlock the releasable lockmechanism, and mechanism connecting the cam to the cross slide for simultaneously moving the cl0 SS.-"S1ide inwardly on looking movement and outwardly on unlocking movement, said cross .slide'having a cross feed screw, and said mechanism including gearing for rotating said screw and adjustable links, the :length of one of said links being adjustable to change the extent of inward "and outward travel of the cross slide.

3. A control mechanism for alathe having a tool carrier, a longitudinal feed screw, releasable lock means operatively connecting the tool carrier and thejlongitudinal feed screw, and a manually settable cross slide on said'tool carrier, comprising a cam movable to lock and unlock the releasable lock mechanism, and mechanism connecting the cam to the cross slide for simultaneously moving the cross slide inwardly on locking movement and outwardly on unlocking movement, said mechanism including a slot in said cam, aslide element in said slot, gearing for the cross slide including a cross feed screw and a cross feed pinion and linkage operatively connecting the slide element to the cross feed pinion.

4. A control mechanism for a lathe having a tool carrier, a longitudinal feed'screw, releasable lock means operatively connecting the tool carrier 5 6 and the longitudinal feed screw, and a manually REFERENCES CITED settable cross slide on said tool carrier, compris- The following references are of record in the ing a cam movable to lock and unlock the reme of this patent; leasable lock mechanism, and mechanism connecting the cam to the cross slide for simul- 5 UNITED STATES PATENTS taneously moving the cross slide inwardly on Number Name Date locking movement and outwardly on unlocking 143,898 Gleason Oct. 21, 1873 movement, said mechanism including a slot in 319,943 Wohlenberg June 9, 1885 said cam, a slide element adjustably secured in 392,337 Holly Nov. 6; 1888 said slot, gearing for the cross slide including a 1 FOREIGN PATENTS cross feed screw and a cross feed pinion and T linkage operatively connecting the slide element Number Country Date to the cross feedpinion. ,7 1,410 Great Britain June 9, 1853 V KENNETH C. JOHNSON. 

